So, the blank tank in my '91 Scamp is leaking. Although the tank appears from the top to be a one-piece unit, the bottom of it is actually a large ledge that is caulked to the inside about one inch from the bottom of the tank. My caulk is leaking and causing a bit of a mess in the shower. Thankfully, we never use it for number two! I know it's the caulk as I removed the whole assembly, put a plug in the large outlet and filled it with water. We had a small trickle out the edges where the panel is caulked in to place.

Has anyone repaired this with success or am I better off replacing the black tank? I hate to "fix" things with caulk so wondering what others have done here. Thanks.

So, the blank tank in my '91 Scamp is leaking. Although the tank appears from the top to be a one-piece unit, the bottom of it is actually a large ledge that is caulked to the inside about one inch from the bottom of the tank. My caulk is leaking and causing a bit of a mess in the shower. Thankfully, we never use it for number two! I know it's the caulk as I removed the whole assembly, put a plug in the large outlet and filled it with water. We had a small trickle out the edges where the panel is caulked in to place.

Has anyone repaired this with success or am I better off replacing the black tank? I hate to "fix" things with caulk so wondering what others have done here. Thanks.

Bryan I believe someone else just had this same problem and fix a couple weeks ago. Hope they chime in as I couldn't find it for you .

I have never seen a Scamp blackwater tank caulked in place. The P.O. may have had the leaking issue. The tank is installed with 4 lag bolts or screws and a wax ring is set around the exit hole. The wax ring is to keep shower water from running out the pipe exit hole. The only way to remove the tank is to cut off the tail pipe and replumb the 3" drain line. The tail piece screws into the bottom of the tank for removal and inst. It's best to order the ABS pipes from Scamp before you start removal.
You need to pull the toilet to find the leak. If the tail piece is leaking the wax ring prevents the fluids from entering the shower pan it will leak to the ground. The tank is made of a plastic which not much sticks to it so If it were mine I would consider replacement. You can order a tank alone.
Now the next issue, Scamp is currently using the 711-M28 Sealand Dometic toilet and tank. The older trailers not sure when but around pre mid 1990's had 911 Sealand's. You need to figure out what toilet you have.
The 911 will bolt to the new tank but it wont fully flush due to the flush lever hitting the tank. You will have to modify something to make it work or order a new tank and toilet. There are threads on 911/711 tank issues.
Eddie

I know that it's not caulked to the shower pan as the whole assembly is already removed. The bottom of the tank appears to be a separate "plate" that is caulked in to place. This is where it's leaking. Video attached showing the caulk seam location. Between having to possibly buy a new toilet assembly and a three-way fridge, this is getting to be half the price I paid for the trailer when I bought it several years ago!

I know that it's not caulked to the shower pan as the whole assembly is already removed. The bottom of the tank appears to be a separate "plate" that is caulked in to place. This is where it's leaking. Video attached showing the caulk seam location. Between having to possibly buy a new toilet assembly and a three-way fridge, this is getting to be half the price I paid for the trailer when I bought it several years ago!

Look around for a plastic fabricator who works with polypropylene. They can use a hot air welder to seal your leak; most tanks are poly. If not they can definitely solvent weld the crack.

Thought I would take a few pictures so people can see what this looks like. I'm surprised that the seam where the two parts join is at the bottom. You would have thought they would have put the seam at the top to avoid it being totally submerged.

First close up look of a Model 911 tank underside I had seen. (Poor design.) That explains why this tank was discontinued and replaced with a model 711 tank which is a one piece molded design. Thanks for posting pictures.
Eddie

Been away but now I am back and thanks for all the picts Bryan.
I sure wish I had them before I had left the trailer at the shop for the repair.
Come to find out it was not broken but just the seal.
Cost was a bit high but the hourly rate kills us all.
But a big guy like me with arthuritis in the hands these tight spots are no longer a home fix for us, sad to say.
Thanks again